Vulcanized fibrous rubber composition



Patented Feb. 19, 19 29.

PATENT, OFFICE.

CYRUS FIELD WILLARD, OI SAN DIEGO,- CALIFORNIA.

I VULCANIZED FIBROUS RUBBER COMPOSITION.

ll o Drawing.

My composition consists of devulcanized rubber, which has been devulcanized, in the presence of the fiber without destroying the fiber, by the processes for devulcanizing rubher covered by Patents Nos. 1,322,077; 1,322,151 and 1,322,152, issued to me, Nov. 18, 1919, a vul'canizing agent, an accelerator, pigments, compounds and fillers mixed in such proportions as to make the product thus 10 obtained best adapted to the purpose for which it is designed. The basic mixture of rubber and fiber when dried is in a flocculent mass and it is considered good factory practice tofirst form such mass into a sheet, by

the action of a sheeting-out mill and then b means of a suitable mixin mill reform suc sheet and mix the particfies thereof with a vulcanizing agent, an accelerator or accelerators-pigments, compounds and fillers. The

resultant final mixture is then formed into sheet-shape and vulcanized to make a floor covering superior to linoleum. When this composition of matter is to be used for floor covering, I have found that the best results are obtained when combined in about the following proportions.

Parts Devulcanized rubber and fiber 65 Ferric oxide 6 3o Sulfur"; 3 Parafiine wax 2 Thiocarbanalide ..i.. .5 Calcium hydrate 2.5 Petrolatum 4 Wood flour- 17 It is evident that these proportions may be varied within certain limits depending on the pur ose for which the mixture when re-vulcanized is to be used.

Application filed December 26, 1925. Serial No. 77,872.

These ingredients are mingled and mixed in the following manner :The mixed devulcanized rubber and fiber as it comes from the d'evulcanizing kettles is dried to the necessary degree of absence of moisture and when dried it is sheeted and the necessary vulcanizing agent or agents, accelerators, pigments, compounds and fillers are mixed with it when on the usual mixin mill used in rubber factories. or' the dried ru her and fiber may be mixed in any other suitable manner in a mixing machine of which the Banbury mixer is an example. It may then run over a warmingup? mill and then to a calender, such as might i be done if any new crude rubber were used. It is then vulcanized in any desired manner.

This sheeted-out material may be vulcanized in a sheet of any desired thickness and length in a belt press or by any other method of vulcanization. When used for floor covering, it may range in thickness from inch to inch and may be 72 inches wide and 30 yards long.

Having described my invention, what I claim is: i

p The herein described composition oflnatter 'for floor coverin and other purposes, consistin of substantlall sixty-five parts of mixed ru ber, and fiber, t iree parts of sulfur, one-half part of thiocarbanalide, two and onehalf parts of calcium hydrate, four parts of petrolat-um, six parts of ferric oxide, two parts of parafline wax and seventeen parts of wood floor, mixed and sheeted out together in a sheet of any desired thickness, width and length and vulcanized in any desired manner, substantially as described and for the purpose specified.

In witness whereof I have aflixed my signature hereunto.

CYRUS FIELD WILLARD. 

